Turkey’s shooting down of a Russian jet – and the so far unconfirmed death of its two pilots, said to have been shot by Syrian Turkmen rebels loyal to the Islamic militant group, al Nusra—is the most severe blow that Turkish-Russian relations have suffered in decades.

An image grab made from a video shows a burning Russian fighter jet coming down after being shot down near the Turkish-Syrian border on Nov 24. (AFP photo)

Russia and Turkey, at loggerheads since the end of September when Russian troops moved into Syria to back President Bashar al-Assad, both claim to be the innocent party. Though there have been four alleged Russian incursions into Turkish airspace since the beginning of October, Moscow was quick to deny any such action this time. Turkey’s military say that the jet was shot down only after being given ten warnings in the course of five minutes and ignoring them.

The plane fell into Syrian not Turkish territory which indicates it must at least have been very close to the border if it was in Turkey’s airspace. The area, described by Turkey as being held by Turkmens, is part of the territory of al-Nusra, an affiliate of al-Qaeda. Turkish officials were saying late on Tuesday afternoon that they believe both airmen are alive and that efforts are under way for their release.

But if the two airmen do turn out to have killed by free fire, contrary to the rules of war, it would add a further very serious twist to what appears a very dangerous head-on political and diplomatic confrontation between Turkey (which wants to overthrow President Assad and replace him with a Sunni Government dominated by the Muslim Brotherhood) and Russia, which is seeking to prop Assad up in the coastal regions of Syria and preserve a military and naval presence for itself on the Mediterranean.

In both Moscow and Ankara today, ambassadors of each country were summoned to face strong protests from the government of the other country. In Turkey, the Foreign Ministry also called in the ambassadors of the United States, Britain, France, and China to discuss the situation with them.

The shooting came amid intense diplomatic efforts by Turkish and Russian diplomats to avert a confrontation. Last week Turkey handed Russia a note explaining its fears of a possible collision between the two countries over Syria and suggesting ways of preventing it. Sergei Lavrov, the Russian Foreign Minister, was due to meet his Turkish counterpart, Feridun Sinirlioğlu in Istanbul on Wednesday, in the hope that some sort of agreement could be reached. In the wake of today’s events, Lavrov’s visit has been called off and Russia has even taken the unprecedented step of warning its nationals to stay away from Turkey because of the danger of terrorism there.

President Vladimir Putin speaking soon afterwards described the downing as “a stab in the back by the accomplices of terrorists,” his strong language suggesting that Russia is increasingly inclined to accuse Turkey of involvement in terrorism in Syria and in no mood to seek an early agreement.

The Russian President was in Teheran on Monday this week, evidently working on ways to step up military and political cooperation over Syria between the two countries. It will not have passed unnoticed in the discussions that the two countries are also Turkey’s major energy suppliers, accounting for about three quarters of its gas imports between them and over a third of its oil.

Geography means that Turkey will always be a crucially important transit country for both Iranian and Russian exports, so any kind of squeeze on exports to Turkey would hit both countries, especially perhaps Iran as its starts to recover after the lifting of US sanctions. Nonetheless it looks as if for Russia at least, its foreign policy and strategic interests are currently at odds with its energy policy – and that President Putin will put strategic interests first. Turkey faces the further problem that its first nuclear energy plant is being built by the Russians and will be partly Russian-managed for decades after that.

In the US and among some of Turkey’s other western allies, the shooting down was being seen on Tuesday evening as the failure of a brinkmanship policy by Putin, suggesting the Russian leader underestimated the determination of Turkey’s president. Yet in Syria, it is Russia which seems to enjoy flexibility of action, with planes, bases, troops on the ground—and the support of an internationally recognized government–albeit a beleaguered one.

The loss of one jet does not upset this pattern or undo the fact that Russia’s presence in Syria makes Turkey’s bid for regime change there look even more expensive and risky.